Friday's power cut prevented us getting this to you on Friday. Here's our take on the text messages that you pay for but never arrive.

Mobile phone operators are charging customers for text messages that are never received.

The popularity of pre-pay handsets among teenagers has also led to a growth in text messaging, which many use as a way of keeping the cost of calls down. But many of these people will be unaware they are being charged for dumped messages.

Orange admitted last week it had deleted text messages sent to Radio 1, which was running a quiz where 11 million participants answered questions via text messages.

But other operators denied deleting messages and said customers would only be charged for unsent messages in 'exceptional circumstances'.

"We haven't ever had this problem where we've needed to delete messages," said a spokeswoman at BT Cellnet. "There are, however, situations where we will charge for text messages that aren't delivered."

BT Cellnet said that, where the recipient's phone was full of messages, if his phone had been left off for more than 17 days or if the message was sent to the wrong number the sender would be charged even though the message had not been delivered.

"We try to deliver all the messages and those that do not go through first time are automatically resent," said a spokesman at Vodafone. "We haven't ever needed to delete messages."

But the Mobile Marketing Association says it's common practice for operators to delete messages.

"There is limited inbound capacity and networks have to delete messages at varying rates," said MMA spokesman Steven Wunker.

Even though the customer may be completely unaware that they have been charged for an unsent message, and are even less likely to be aware that their message has been deleted, according to Oftel operators are completely within their rights to do this.

"There is no law to stop operators doing this, it is down to contractual terms," said a spokeswoman at Oftel. "But it is rare for messages to be deleted."

An extremely wide clause in Orange's terms and conditions reads: "We will not be liable to you if we are unable to perform an obligation or provide services to you because of any factor outside our control".

But this does not make it clear that customers will be charged even when messages have not been delivered.

"Although we do encourage companies not to charge for messages that haven't been sent through we cannot demand this," said a spokeswoman at Oftel. "It is down to company policy."

But the Mobile Marketing Association said people should not expect operators to deliver all messages.

"There is only limited storage capacity [on networks] and people shouldn't expect operators to store their message until a time when it can be sent," said Wunker, MMA spokesman. "It's like with emails. You cannot guarantee an email will be read or delivered to the correct recipient but the sender will still expect to be charged."

Orange and Vodafone blame radio stations for not giving notice of competitions that could lead to an influx in text messages.

"If broadcasters gave us notice that a number would be receiving millions of calls we could make sure enough lines were available, but without notice a backlog is inevitable," said a spokesman for BT Cellnet.

But whether or not a bottleneck could be prevented, operators should be doing more to prevent their customers being billed for messages that aren't sent.

"Operators should do whatever they can to prevent customers being billed [for unsent messages] but it is impossible for them to notify each customer when the situation occurs," said a spokeswoman at Oftel.